Membrane electrode assembly

a membrane electrode and assembly technology, applied in the field of fuel cells and electrolyzers, can solve the problems of large amount of sealing material waste during the cutting process, low dimensional stability, and compression tolerance reduction, and achieve the effects of preventing gasket straining, improving sealing structure, and improving dimensional stability and reagent gas insulation

Inactive Publication Date: 2007-08-30
AUTO JUNTAS UNIPERSONAL
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Benefits of technology

[0011] The author of the present invention has found, after intensive research, that placing an integrated reinforcing material in the gasket, surrounding both the membrane electrode assembly and the passages for gases, fluids, and, if applicable, clamping elements, allows solving the problems posed in the state of the art, providing a membrane electrode assembly with an improved sealing structure for use in fuel cells and electrolyzers. By using this type of assembly its dimensional stability and reagent gas insulation are considerably improved, and also gasket straining is prevented while at the same time maintaining the compressive force between the elements comprising the fuel cell, which makes the present invention a significant improvement over the membrane electrode assemblies with a sealing structure existing in the state of the art.

Problems solved by technology

However, these structures force the design of very thin gaskets such as not to increase fuel cell size, which causes a reduction of compression tolerance.
As an additional disadvantage, a large amount of sealing material is wasted during the cutting process.
However, a problem that occurs with this type of structures is its low dimensional stability since straining usually occurs in the sealing material due to internal stresses and contraction stresses during the injection process.
However, since the passages for reagent gases are integrated in the gasket, these reduce the consistency of the assembly by reducing the capacity of the reinforcement in order to stabilize the MEA body.

Method used

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Examples

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example 1

Preparation of a Membrane Electrode Assembly with a Reinforced Sealing Structure.

[0088] The first step for manufacturing this assembly is cutting of the carbon cloth, which forms the porous gas diffusion layers, and of the membrane. To this end two pieces of carbon cloth with a microporous layer on one of its sides have been cut to dimensions of 200×200 mm. Likewise, a piece of proton exchange membrane, specifically a Nafion® 112 membrane, is also cut with equal dimensions.

[0089] As a second step the catalytic ink is prepared by methods that have already been amply described in the state of the art. The same composition can be used for the anode and the cathode, or a different ink composition may be used for the anode and the cathode. The ink contains platinum-on-carbon, with 20% platinum, an ionomer in the form of a 5% by weight solution of Nafion® and isopropyl alcohol. To obtain the ink, these components are mixed and stirred using ultrasound.

[0090] Once the catalytic ink is ...

example 2

Testing a Fuel Cell With a Set of Membrane Electrode Assemblies With a Reinforced Sealing Structure.

[0101] A fuel cell is assembled by stacking 15 cells formed by membrane electrode assemblies such as the one described above. The active area in each cell is 190 mm×190 mm. The cell is tested using industrial grade hydrogen as fuel and ambient air as oxidizer. The hydrogen is fed through the dead-end system, which consists in keeping the cathode closed and venting with a certain frequency, in this case every 20 seconds. The air is supplied with a stoichiometric flow rate of 2.0. Pressures in the anode and cathode are 30 kPa, and the fuel cell stays at a temperature of 60° C. During the test a maximum power of 1625 W is obtained, with a voltage of 7.2 V, such that a power density of 300 mW / cm2 is obtained.

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Abstract

The present invention relates to an assembly with a reinforced sealing structure for its use in fuel cells and electrolyzers, comprising a membrane electrode assembly (23) and a sealing structure (S) surrounding said membrane electrode assembly (23), said sealing structure (S) comprising a gasket (G), a reinforcing material (4) integrated in said gasket and reagent gas and coolant fluid openings (10) for the passage of reactant gases and coolant fluid.

Description

CROSS REFERENCE TO RELATED APPLICATIONS [0001] This application claims priority under 35 U.S.C. §119(a) of European Patent Application No. 06380036.1 for “Membrane Electrode Assembly,” filed on Feb. 24, 2006 in the name of Pedro Sanchez Diaz, which is incorporated by reference herein in its entirety. FIELD OF THE INVENTION [0002] The present invention falls within the scope of fuel cells and electrolyzers, and more specifically it is aimed at an assembly with an improved sealing structure. STATE OF THE ART [0003] In recent decades there is an important increase in production, storage and energy conversion methods. Due to the progressive depletion of the fossil fuel reserves, such as oil, coal, and natural gas reserves, and due to their negative effects on the environment, new technologies are being developed to generate clean, efficient and decentralized energy. In this sense, fuel cells as a feed system for an electric engine are a very efficient alternative, for example, to using ...

Claims

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Application Information

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Patent Type & Authority Applications(United States)
IPC IPC(8): H01M2/08H01M8/02H01M8/10H01M4/94C25B9/00
CPCH01M8/0273H01M8/0276H01M8/0284Y02E60/50H01M8/242H01M8/248H01M2008/1095H01M8/0286H01M8/2483H01M8/0267H01M8/0258
Inventor DIAZ, PEDRO SANCHEZ
Owner AUTO JUNTAS UNIPERSONAL
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